Projecting apparatus

ABSTRACT

A projecting apparatus for protecting an image onto a screen includes an image module, a first light reflection device and a lens. The image module is for providing a beam of first light, The first light reflection device has a first reflection surface disposed movably relative to the image module for reflecting the first light to form a beam of second light. The lens is for projection the image on the screen according to the second light. Moving the first light reflection device along the beam of first light or second light can adjust the location of the image on the screen in a first direction.

This application claims the benefit of Taiwan application Serial No.94124637, filed Jul. 21, 2005, the subject matter of which isincorporated herein by reference

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to a projecting apparatus, and moreparticularly to a projecting apparatus, which utilizes a prism or mirrorto perform light shift and focus adjustment.

2. Description of the Related Art

In the present high-level projecting apparatus, the lens is usuallyequipped with mechanism for lens shift and focus adjustment to adjustthe location of the image projected onto a screen and the focus locationof the image relative to the screen in addition to function of adjustingimage size and brightness. However, these delicate mechanisms used inthe lens increase the difficulty in designing and manufacturing the lensoriginally complicated.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a projectingapparatus. By using a prism or mirror to perform light shift andprojection image adjustment, the projecting apparatus achieves lightshift and focus functions without influencing projection light angles.Therefore, the (complication in lens design and manufacture as well asthe system manufacturing cost can be reduced.

The invention achieves the above-identified object by providing aprojecting apparatus for projecting an image onto a screen. Theprojecting apparatus includes an image module, a first light reflectiondevice and a lens. The image module is for providing a beam of firstlight. The first light reflection device has a first reflection surfacedisposed movably relative to the image module for reflecting the firstlight to form a beam of second light. The lens is for projecting theimage on the screen according to the second light. Moving the firstlight reflection device can adjust the location of the image on thescreen in a first direction.

Other objects, features, and advantages of the invention will becomeapparent from the following detailed description of the preferred butnon-limiting embodiments. The following description is made withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial solid view of a projecting apparatus according to apreferred embodiment of the invention.

FIG. 2A is a schematic diagram of adjusting the perpendicular locationof the image R on the screen S by using the image shift device 120 ofFIG. 1 is shown.

FIG. 2B is another schematic diagram of adjusting the perpendicularlocation of the image on the screen by using the image shift device ofFIG. 1.

FIG. 3A is a schematic diagram of adjusting the horizontal location ofthe image R on the screen S by using the image shift device 120 of FIG.1 is shown.

FIG. 3B is another schematic diagram of adjusting the horizontallocation of the image on the screen by using the image shift device ofFIG. 1.

FIG. 4 is a solid view of the second structure of the image shift deviceof FIG. 1.

FIG. 5 is a solid view of the third structure of the image shift deviceof FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a partial solid view of a projecting apparatusaccording to a preferred embodiment of the invention is shown. Theprojecting apparatus 100 is used for projecting an image R onto a screenS. The projecting apparatus 100 includes an image shift device 120, animage module 110 and a lens 130. The image module 110 such as a digitalmicromirror device (DMD), is for reflecting a beam of projection lightLo emitted from a light source module (not shown in the figure) toprovide a beam of first light L1. The image shift device 120 includes afirst light reflection device 112 and a second light reflection device114. The first light reflection device 112 and the second lightreflection device 114 are prisms for instance. The first lightreflection device 112 has a first reflection surface 112 a forreflecting the first light L1 to form a beam of second light L2. Thesecond light reflection device 114 has a second reflection surface 114 afor reflecting the second light L2 to form a beam of third light L3. Thelens 130 is used for projecting the third light L3 onto the screen S toform the image R

As shown in FIG. 1, the central axis C1 of the first reflection surface112 a is located on the X-Y plane formed by the central connection lineX connecting the centers of the first light reflection device 112 andthe second light reflection device 114, and the optical axis Y of theimage module 110. The central connection line X is vertical to theoptical axis Y while the central axis C1 of the first reflection surface112 a is inclined by 45 degrees against the optical axis Y Besides, thecentral axis C2 of the second reflection surface 114 a is located on theX-Z plane formed by the central connection line X of the first lightreflection device 112 and the second light reflection device 114, andthe optical axis Z of the lens 130. The central connection line X isvertical to the optical axis Z while the central axis C2 of the secondreflection surface 114 a is inclined by 45 degrees against the opticalaxis Z

It is noted that the XY plane is perpendicular to the X-Z plane and thusthe central axis C2 of the second reflection surface 114 and the centralaxis C1 of the fist reflection surface 112 are not coplanar Therefor,the locations of the image R relative to the screen S in a horizontaldirection (X-direction) and a perpendicular direction (Y-direction) canbe adjusted by changing the locations of the first light reflectiondevice 112 and second light refection device 114, In the followingdescription, it is illustrated accompanied with drawings how theinvention adjusts the horizontal and perpendicular locations of theimage FR relative to the screen S via the first light reflection device112 and the second light reflection device 114.

Referring to FIG. 2A, a schematic diagram of adjusting the perpendicularlocation of the image R on the screen S by using the image shift device120 of FIG. 1 is shown. The lens 130 is not shown in the figure forillustration convenience. The second light reflection device 114 is notshifted while the first light reflection device 112 is shifted left (asshown by the arrow W1) in the X-direction. At the time, the incidentpoint of the first light L1 going into the first reflection surface 112a is shifted upward from the point A1 to A2 while the incident point ofthe second light L2 going into the second reflection surface 114 a isshifted upward from the point B1 to B2. As a result, the location of thethird light L3 projecting onto the screen S is also shifted upward fromthe point D1 to D2. Similarly, the second light reflection device 114 isnot shifted while the first light reflection device 112 is shifted right(as shown by the arrow W2) in the X-direction. The incident point of thefirst light L1 going into the first reflection surface 112 a is shifteddownward from the point A1 to A3 while the incident point of the secondlight L2 going into the second reflection surface 114 a is shifteddownward from the point B1 to B3, As a result, the location of the thirdlight L3 projecting onto the screen S is also shifted downward from thepoint D1 to D3. Therefore, the location of the image R on the screen Sin the Y-direction (perpendicular direction) can be adjusted by shiftingthe first light reflection device 112 in the X-direction (horizontaldirection).

Furthermore, as shown in FIG. 2B, the second light reflection device 114is not shifted while the first light reflection device 112 is shiftedupward (as shown by the arrow W3) in the Y-direction. The incident pointof the first light L1 going into the first reflection surface 112 a canalso be shifted upward from the point A1 to A2. As a result, thelocation of the third light L3 projecting onto the screen S can also beshifted upward from the point D1 to D2. Similarly, the second lightreflection device 114 is not shifted while the first light reflectiondevice 112 is shifted downward (as shown by the arrow W4) in theY-direction. The incident point of the first light L1 going into thefirst reflection surface 112 a can also be shifted downward from thepoint A1 to A3. As a result, the location of the third light L3projecting onto the screen S can also be shifted downward from the pointD1 to D3. Therefore, the location of the image R on the screen S in theperpendicular direction can be adjusted by shifting the first lightreflection device 112 in the Y-direction (perpendicular direction).

As shown in FIG. 2A and FIG. 2B, when the first light reflection device112 is shifted in the X-direction or the Y-direction, the first light L1is reflected by the first reflection surface 112 a via the image module110 to form the second light L2 while the second light L2 is reflectedby the second reflection surface 114 a to form the third light L3 forprojecting onto the screen S. The total length of the optical path fromthe image module 110 to the screen S is decreased from ( A0A1+ A1B1+B1D1) to ( A0A2+ A2B2+ B2D2) (∵ A0A2< A0A1) or increased from ( A0A1+A1B1+ B1D1) to ( A0A3+ A3B3+ B3D3) (∵ A0A3> A0A1). Therefore, the focuslocation of the image R relative to the screen S can also besimultaneously adjusted by shifting the first light reflection device112 in the X-direction (or Y-direction).

Referring to FIG. 3A, a schematic diagram of adjusting the horizontallocation of the image R on the screen S by using the image shift device120 of FIG. 1 is shown. The lens 130 is not shown in the figure forillustration convenience. The first light reflection device 112 is notshifted while the second light reflection device 114 is shifted left (asshown by the arrow W5) in the X-direction. At the time, the incidentpoint of the first light L1 going into the first reflection surface 112a is not shifted and at the same point A1 while the incident point ofthe second light L2 going into the second reflection surface 114 a isshifted left from the point B1 to B4. As a result, the location of thethird light L3 projecting onto the screen S is also shifted left fromthe point D1 to D4. Similarly, the first light reflection device 112 isnot shifted while the second light reflection device 114 is shiftedright (as shown by the arrow W6) in the X-direction. T ie incident pointof the first light L1 going into the first reflection surface 112 a isnot shifted and at the same point A1 while the incident point of thesecond light L2 going into the second reflection surface 114 a isshifted right from the point B1 to B5. As a result, the location of thethird light L3 projecting onto the screen S is also shifted right fromthe point D1 to D5, Therefore, the location of the image R on the screenS in the horizontal direction can be adjusted by shifting the secondlight reflection device 114 in the X-direction (horizontal direction).

In addition, as shown in FIG. 3B, the first light reflection device 112is not shifted while the second light reflection device 114 is shiftedbackward (as shown by the arrow W7) in the Z-direction. The incidentpoint of the second light L2 going into the second reflection surface114 a can also be shifted left from the point B1 to B4. As a result, thelocation of the third light L3 projecting onto the screen S can also beshifted left from the point D1 to D4. Similarly, the first lightreflection device 112 is not shifted while the second light reflectiondevice 114 is shifted forward (as shown by the arrow W8) in theZ-direction. The incident point of the second light L2 going into thesecond reflection surface 114 a can also be shifted right from the pointB1 to B5. As a result, the location of the third light L3 projectingonto the screen S is also shifted right from the point D1 to D5.Therefore, the location of the image R on the screen S in the horizontaldirection can be adjusted by shifting the second light reflection device114 in the Z-direction.

As shown in FIG. 3A and FIG. 3B, when the second light reflection device114 is shifted in the X-direction of the Z-direction, the first light L1is reflected by the first reflection surface 1,12 a via the image module110 to form the second light L2 while the second light L2 is reflectedby the second reflection surface 114 a to form the third light L3 forprojecting onto the screen S. The total length of the optical path fromthe image module 110 to the screen S is increased from ( A0A1+ A1B1+B1D1) to ( A0A1+ A1B4+ B4D4)(∵ A1B4x > A1B1) or decreased from ( A0A1+A1B1+ B1D1) to ( A0A1+ A1B5+ B5D5) (∵ A1B5< A1B1). Therefore, the focuslocation of the image R relative to the screen S can also besimultaneously adjusted by shifting the second light reflection device114 in the X-direction (or Z-direction).

As described above, although the image shift device 120 including towprisms is taken as an example in the invention, the image shift device120 of the invention can also use two mirrors 412 and 414 as shown inFIG. 4 or use two prism sets 512 and 514. The prism set 512 includes twoprisms 512 a and 512 b while the prism set 514 includes two prisms 514 aand 514 b. As long as the central axes C3 and 04 of the mirrors 412 and414 are not located on the same plane, or the central axes C5 and C6 ofthe mirrors 412 and 414 are not coplanar, the purpose of adjusting thehorizontal and perpendicular locations of the image R projected onto thescreen S can be achieved by shifting the mirrors 412 and 414 or theprisms 512 and 514. Therefore, all these are not apart from the scope ofthe invention.

Besides, although the image shift device 120 is exemplified to includethe first light reflection device 112 and the second light reflectiondevice 114 in the invention, the projecting apparatus of the inventioncan also include only the light reflection device 112 disposed movablyrelative to the image module 110 for reflecting the first light L1 toform the second light L2 which in turn is projected via the lens 130 toform an image on the screen S. That is, the second light reflectiondevice 114 is removed from FIG. 1 and the central axis of the lens 130and the screen S is changed to be disposed on the X-axis. The lightreflection device 112 is moved along the beam of first light L1 (i.e.the optical axis Y of the image module 110) or the beam of second lightL2 (i.e. the optical axis X of the lens 130) for adjusting the locationof the image R on the screen S along the Y-direction. Or the projectingapparatus can also include only the light reflection device 114 disposedmovably relative to the image module 110 for reflecting the first lightL1 to form the second light L2 which in turn is projected via the lens130 to form an image on the screen S. That is, the first lightreflection device 112 is removed from FIG. 1 and the central axis of theimage module 110 is changed to be disposed on the X-axis. The lightreflection device 114 is moved along the beam of first light L1 (i.e.the optical axis X of the image module 110) or the beam of second lightL2 (i.e. the optical axis Z of the lens 130) for adjusting the locationof the image R on the screen S along the X-direction.

The projecting apparatus and image shift device thereof disclosed by theabove-mentioned embodiment of the invention has the followingadvantages. The purpose of 2-D light shift and focus adjustment can beachieved by using two simples-structure prisms or mirrors, which are notcoplanar, to reflect the light emitted from the image module Withoutneed of the conventional complicated mechanism for lens shift and focusadjustment equipped in the lens, the complication in designing andmanufacturing the lens can be reduced and the cost for manufacturing thesystem can be lowered down.

While the invention has been described by way of example and in terms ofa preferred embodiment, it is to be understood that the invention is notlimited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

1. A projecting apparatus, for projecting an image onto a screen, theprojecting apparatus comprising: an image module, for providing a beamof first light; a first light reflection device, having a firstreflection surface, disposed movably relative to the image module forreflecting the first light to form a beam of second light; and a lens,for projecting the image on the screen according to the second light;wherein moving the first light reflection device along the beam of firstlight or second light can adjust the location of the image on the screenin a first direction.
 2. The projecting apparatus according to claim 1,wherein the first light reflection device is a prism or a mirror.
 3. Theprojecting apparatus according to claim 1, wherein the optical axis ofthe first reflection plane is inclined by 45 degrees against the opticalaxis of the image module.
 4. The projecting apparatus according to claim3, wherein the first reflection device moves along the optical axis ofthe image module for adjusting the location of the image on the screenalong the first direction.
 5. The projecting apparatus according toclaim 3, wherein the first reflection device moves along the opticalaxis of the lens for adjusting the location of the image on the screenalong the first direction.
 6. The projecting apparatus according toclaim 3, further comprising a second light reflection device having asecond reflection surface for reflecting the beam of second light toform a beam of third light, wherein a central axis of the secondreflection surface and a central axis of the first reflection surfaceare not coplanar, the lens is for projecting the third light onto thescreen to form the image and the second light reflection device is foradjusting the location of the image on the screen along a seconddirection.
 7. The projecting apparatus according to claim 6, wherein thefirst light reflection device and the second light reflection device areprisms.
 8. The projecting apparatus according to claim 6, wherein thefirst light reflection device and the second light reflection device aremirrors.
 9. The projecting apparatus according to claim 6, wherein acentral connection line of the first light reflection device and thesecond light reflection device and an optical axis of the image moduleform a first plane and a central axis of the first reflection surface islocated on the first plane.
 10. The projecting apparatus according toclaim 9, wherein the central connection line is perpendicular to theoptical axis of the image module and the central axis of the firstreflection surface is inclined by 45 degrees against the optical axis ofthe image module.
 11. The projecting apparatus according to claim 10,wherein the central connection line and the optical axis of the lensform a second plane, and the central axis of the second reflectionsurface is located on the second plane.
 12. The projecting apparatusaccording to claim 11, wherein the central connection line isperpendicular to the optical axis of the image module and the centralaxis of the second reflection surface is inclined by 45 degrees againstthe optical axis of the lens.
 13. The projecting apparatus according toclaim 12, wherein the first plane is perpendicular to the second plane.14. The projecting apparatus according to claim 6, wherein the firstlight reflection device is shifted along a central connection line ofthe first light reflection device and the second light reflection deviceto adjust the location of the image on the screen in the firstdirection.
 15. The projecting apparatus according to claim 6, whereinthe first light reflection device is shifted along an optical axis ofthe image module to adjust the location of the image on the screen inthe first direction.
 16. The projecting apparatus according to claim 6,wherein the second light reflection device is shifted along a centralconnection line of the first light reflection device and the secondlight reflection device to adjust the location of the image on thescreen in the second direction.
 17. The projecting apparatus accordingto claim 6, wherein the first light reflection device is shifted alongan optical axis of the lens to adjust the location of the image on thescreen in the second direction.
 18. The projecting apparatus accordingto claim 6, wherein the first light reflection device and the secondlight reflection device are used for adjusting a focus location of thethird light relative to the screen.
 19. The projecting apparatusaccording to claim 6, wherein the first direction is a perpendiculardirection and the second direction is a horizontal direction.
 20. Theprojecting apparatus according to claim 1, wherein the image module is adigital micromirror device (DMD).